Telephony.



M. L. JOHNSON. TELEPHONY. APPLICATION FILED AUG 10, 1911.

1,045,034. Patented Nov. 19, 1912.

MT 5885 INVENTOR E5 MORTON L JOHNSON ATTORNEY 1 the accompanying drawings, forming a part UNr-rn STATES arnnr enrich. 1

MORTON L. JOHNSON, or CHICAGO, ILLINOIS, AssIGNon TO GORWIN TELEPHONE MANUFACTURING COMPANY, or CHICAGO, ILLINOIS, A COBPDRATIQN or ILLINOIS.

TELEPHONY.

To all whom it my concern: v

Be it known that I, MORTON L. JOHNSON, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement-in Telephony, of which the following is a full, clear, concise, and exact description, reference being bad to of this specification.

,. My invent-ion relates v to telephone ex change systems and resides in the provision of a pilot clearing out indicator under the control of line signal devices when employed as clearing out indicators.

I will explain my invention more fully by reference to the accompanying drawing showing the preferred embodiment thereof and which illustrates two common battery lines extending-from telephone stations to an exchange. 1 I

Each telephone line extends by its limbs 1 and 2 from substations to an exchange where these limbs terminate in line springs 3 and 4 of a spring jack 5. The apparatus at each ofthe substations to which the lines 1, 2 extend includes .a telephone switch hook 6 .connectcd with the line 1, a telephone receiver. 7 a telephone transmitter 8, a signal receiving hell 9. and a condenser 10 in the signal bell bridge. The normal contact of, the switch hook 6 serves to complete the connection of the signal bell bridge between the sides of the telephone line when the receiver is upon the switch hook and the alternate contact of the switch hook serves to establish the telephone bridge when the receiver is oil? its switch hook.

In initiating a call a circuit is established at the receiver switch'hook and its alternate contact which may be traced from the upper pole of the battery 1l,\the winding of the line pilot relay 12, whichxiswell known to those skilled in the art. the line Spring 4 and-its contact, the winding of the line signal device 13, the telephone transmitter 8 at the calling station,.the telephone receiver '7 at that station, the associate switch hook 5 nal to the operator. The operator, in re- Specification of Letters Patent. v Patented Nov. 19, 1912. Application filed August 10, 1911 Serial No. 643,338.

sponse' to this signal, inserts the answering plug 15 of a link circuit into the jack 5- of 16 illustrated, to include her telephone set 17 in circuit with the line to ascertain the connection desired. Assuming thata connection is to be established between the calling line shown at the right of the drawing and the line shown at the left of the drawing, the operator inserts the connecting plug 18 that is companion 'to the plug 15 vinto the jack of the wanted line and operates the usual ringing key 19'to include the calling and thereby in circuit withthe signal receiver 9 at the station to be called When the plugs are inserted in the jacks a battery 21 is included in circuit with both lines so enerator 20 inbridgeof the cord circuit that thecalling partys signal device 13 inserted in the jack, as illustrated at the I right of the drawing. Each line signal device 13 has a switch.23 whose contacts are closed when the signal device is deenergized which. is when the telephone receiver of the associate line is upon its switch hook as illustrated at the left in the drawing. When the receiver is free of its switch hook the contacts of the associate switch 23 are open as illustrated at the rightof the drawing. each line are in serial relation with the clearing out pilot signal 24, this pilot signal being common to the switches 22, 23 ot a plurality of lines. The conductor in which the common clearing out pilot signal 24 is included and which conductor is common to the switches 22. 23 of the lines, includes a grounded battery 25 and is connected with a conductor 26 that extends to the lower contacts of the switches 23. The armatures of the signal devices 13 operate these lower contacts through the intermediation of insulating fingers 27 when said armatures are attracted, the resilience of the lower contacts permitting their restoration when the armatures are released. Circuit is established through the clearing out pilot signal 2A when The switches 22, 23, of,

' in or out of its is free of its'switch hook. Thus the pilot clearin a plug is inserted within a line jack and when the associate line signal 13 is dotiner'gized, which is when the telephone receiver of the associate station is on its hook. This circuit is openeda't the switch 22, previously closed by the plug, when said plug is withdrawn from its jack. This circuit is also opened at the switch 23 with the plug jack when the telephone receiver of the line to Which the jack belongs While I have herein shown and particu- 4 larly described the preferred embodiment of my invention do not wish to be limited to the precise details of construction and circuit arrangement as changes ma readily be made without departing from t e spirit of theinvention. i

Having'thus described my invention, I claim as new-and desire to secure by Letters Patent the following:- 3

1'. A telephone exchange system including telephone lines extending from telephone stations to an exchange; connecting lines in conversation; a signal device individual to and in such association with each line that it is within the control of the telephone station apparatus to convey callinitiating signals and to act as a clearing out indicator when its line has been connected with; a pilot. clearing out signal device common to a plurality of the aforesaid signal devices and adapted to be controlled thereby; and means governed'by the link connectors for bringing the pilot clearing out signal device within the control of a line signal device when the line to which said line signal device belongs is connected with a link connector. I

2. A telephone exchange system including telephone lines extending from telephone stations to an exchange; link connectors for connecting lines n conversation; a signal device individual to and I in such association with each linev that 1t is within the control M Copies of this patent may be obtained for five cents each, by addressing the (Commissioner Washington, D. 0.

a connected station 'ing in line link connectors for the telephone receivers to include said source" of current in circuit with said signal devices; a pilot clearing out signal device common to a plurality of the aforesaid signal a, source of current at the exwhen supportingv the receivers to devices and adapted to be controlled there-f by; and means'governed by the link connectors for bringing the pilot clearing out signal device within the control of a line signal device when the line to which said line signal'device belongs is connected with a link connector. 7

3. A telephone exchange systemincluding telephone lines extending from telephone stations to an exchange and there terminatacks; link connectors for connecting lines 1nconversation and provided with plugs for'insertion in said line jacks;

a signal device individual to and in such association with each line that it is within the control of the line station apparatus to convey call initiating signals and to act as a clearing out indicator when its line has been connected with; a pilot clearing out siignal device common to a plurality of the a oresaid signal devices; each line having two switches lation with said pilot signal device, one of said switches being governed by the signal device. individual to the associate line and having its contacts opened when this signal device is energized and closed when this signal device is deenergized, the second switch being governed by the plug of a connecting link and having its contacts closed thereby when said plug is'inserted within the associate line jack, there being a source of current for inclusion in circuit with said clear ing out pilot signal device, such circuit being established when the contacts of said switches are closed at the same time.

In witness whereof, I hereunto subscribe my name this 24th day of July A. D., 1911:"

MORTON L; JOHNSON: Witnesses: I

individual thereto and in serial reof Patents. 

